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[glibc.git] / libidn / toutf8.c
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1 /* toutf8.c Convert strings from system locale into UTF-8.
2 * Copyright (C) 2002, 2003, 2004 Simon Josefsson
4 * This file is part of GNU Libidn.
6 * GNU Libidn is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * GNU Libidn is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with GNU Libidn; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 #if HAVE_CONFIG_H
23 # include "config.h"
24 #endif
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <errno.h>
30 #include <sys/param.h>
32 #include "stringprep.h"
34 #ifdef _LIBC
35 # define HAVE_ICONV 1
36 # define LOCALE_WORKS 1
37 # define ICONV_CONST
38 #endif
40 #ifdef HAVE_ICONV
41 # include <iconv.h>
43 # if LOCALE_WORKS
44 # include <langinfo.h>
45 # include <locale.h>
46 # endif
48 # ifdef _LIBC
49 # define stringprep_locale_charset() nl_langinfo (CODESET)
50 # else
51 /**
52 * stringprep_locale_charset:
54 * Find out current locale charset. The function respect the CHARSET
55 * environment variable, but typically uses nl_langinfo(CODESET) when
56 * it is supported. It fall back on "ASCII" if CHARSET isn't set and
57 * nl_langinfo isn't supported or return anything.
59 * Note that this function return the application's locale's preferred
60 * charset (or thread's locale's preffered charset, if your system
61 * support thread-specific locales). It does not return what the
62 * system may be using. Thus, if you receive data from external
63 * sources you cannot in general use this function to guess what
64 * charset it is encoded in. Use stringprep_convert from the external
65 * representation into the charset returned by this function, to have
66 * data in the locale encoding.
68 * Return value: Return the character set used by the current locale.
69 * It will never return NULL, but use "ASCII" as a fallback.
70 **/
71 const char *
72 stringprep_locale_charset (void)
74 const char *charset = getenv ("CHARSET"); /* flawfinder: ignore */
76 if (charset && *charset)
77 return charset;
79 # ifdef LOCALE_WORKS
80 charset = nl_langinfo (CODESET);
82 if (charset && *charset)
83 return charset;
84 # endif
86 return "ASCII";
88 # endif
90 /**
91 * stringprep_convert:
92 * @str: input zero-terminated string.
93 * @to_codeset: name of destination character set.
94 * @from_codeset: name of origin character set, as used by @str.
96 * Convert the string from one character set to another using the
97 * system's iconv() function.
99 * Return value: Returns newly allocated zero-terminated string which
100 * is @str transcoded into to_codeset.
102 char *
103 stringprep_convert (const char *str,
104 const char *to_codeset, const char *from_codeset)
106 iconv_t cd;
107 char *dest;
108 char *outp;
109 ICONV_CONST char *p;
110 size_t inbytes_remaining;
111 size_t outbytes_remaining;
112 size_t err;
113 size_t outbuf_size;
114 int have_error = 0;
116 if (strcmp (to_codeset, from_codeset) == 0)
118 #if defined HAVE_STRDUP || defined _LIBC
119 return strdup (str);
120 #else
121 char *p;
122 p = malloc (strlen (str) + 1);
123 if (!p)
124 return NULL;
125 return strcpy (p, str);
126 #endif
129 cd = iconv_open (to_codeset, from_codeset);
131 if (cd == (iconv_t) - 1)
132 return NULL;
134 p = (ICONV_CONST char *) str;
136 inbytes_remaining = strlen (p);
137 /* Guess the maximum length the output string can have. */
138 outbuf_size = (inbytes_remaining + 1) * MAX (7, MB_CUR_MAX);
140 outp = dest = malloc (outbuf_size);
141 if (dest == NULL)
142 goto out;
143 outbytes_remaining = outbuf_size - 1; /* -1 for NUL */
145 again:
147 err = iconv (cd, (ICONV_CONST char **) &p, &inbytes_remaining,
148 &outp, &outbytes_remaining);
150 if (err == (size_t) - 1)
152 switch (errno)
154 case EINVAL:
155 /* Incomplete text, do not report an error */
156 break;
158 case E2BIG:
160 size_t used = outp - dest;
161 char *newdest;
163 outbuf_size *= 2;
164 newdest = realloc (dest, outbuf_size);
165 if (newdest == NULL)
167 have_error = 1;
168 goto out;
170 dest = newdest;
172 outp = dest + used;
173 outbytes_remaining = outbuf_size - used - 1; /* -1 for NUL */
175 goto again;
177 break;
179 case EILSEQ:
180 have_error = 1;
181 break;
183 default:
184 have_error = 1;
185 break;
189 *outp = '\0';
191 if (*p != '\0')
192 have_error = 1;
194 out:
195 iconv_close (cd);
197 if (have_error)
199 free (dest);
200 dest = NULL;
203 return dest;
206 #else /* HAVE_ICONV */
208 const char *
209 stringprep_locale_charset ()
211 return "ASCII";
214 char *
215 stringprep_convert (const char *str,
216 const char *to_codeset, const char *from_codeset)
218 char *p;
219 fprintf (stderr, "libidn: warning: libiconv not installed, cannot "
220 "convert data to UTF-8\n");
221 p = malloc (strlen (str) + 1);
222 if (!p)
223 return NULL;
224 strcpy (p, str);
225 return p;
228 #endif /* HAVE_ICONV */
231 * stringprep_locale_to_utf8:
232 * @str: input zero terminated string.
234 * Convert string encoded in the locale's character set into UTF-8 by
235 * using stringprep_convert().
237 * Return value: Returns newly allocated zero-terminated string which
238 * is @str transcoded into UTF-8.
240 char *
241 stringprep_locale_to_utf8 (const char *str)
243 return stringprep_convert (str, "UTF-8", stringprep_locale_charset ());
247 * stringprep_utf8_to_locale:
248 * @str: input zero terminated string.
250 * Convert string encoded in UTF-8 into the locale's character set by
251 * using stringprep_convert().
253 * Return value: Returns newly allocated zero-terminated string which
254 * is @str transcoded into the locale's character set.
256 char *
257 stringprep_utf8_to_locale (const char *str)
259 return stringprep_convert (str, stringprep_locale_charset (), "UTF-8");